Figure 5. CTRP9 inhibits ox-LDL-induced mtROS accumulation by regulating antioxidant enzyme expression. Human aortic smooth muscle cells (HASMCs) were treated for 72 h with 5 µg/mL cyclodextrin-cholesterol complex to establish VSMC-derived foam cells, which were then incubated with different concentration of CTRP9 (0–10 μg/mL) in the presence of ox-LDL (10 μg/mL) or left untreated (control) for 24 h. (a) mtROS levels were measured using a MitoSOX™ Red mitochondrial superoxide indicator. (b) A JC-1 staining kit was used to detect mitochondrial membrane potential. (c) Western blotting was performed to examine the protein levels of GCLC, Foxo3, GCLM, HO1, SOD2, and NQO1. (d) Quantitative analysis of the expression of oxidant-related proteins. Data are presented as mean ± SD of three independent experiments. **p < 0.01 vs. the control group; #p < 0.05, ##p < 0.01 vs. the 10 μg/mL ox-LDL group.